Goal events such as large reward, small reward, nonreward and so on give rise to internal stimuli which may be conceptualized as memories. These reward related memories become cues for behavior. The purpose of this research project is to determine how such reward related memories control behavior. To this end we shall vary training level as a function of magnitude of partial reward, vary the intertrial interval between trials, vary the number of rewarded trials, vary transitions from one sort of trial to another, e.g., from nonrewarded to rewarded trials, shift animals from a long intertrial interval in acquisition to a short intertrial interval in extinction and vice-versa and manipulate several other variables as well. As well as observing the behavior of rats in the runway, various forms of discrimination learning will be employed, particularly differential conditioning.